Multiple-fuse plug



LE ESEA FQ Sept. 1159 F925 N. M. STEPHENQON MULTIPLE FUSE PLUG Filed Aug. 8, 1925 Patented Sept. 15, 1925.

UNITED STATES PATENT OFFICE.

MULTIPLE-FUSE PLUG.

Application filed August 8, 1923. Serial No. 656,318.

To all whom it may concern: 7

Be it known that I, NORMAN M. Brenner:- SON, a citizen of the United States, residing at San Francisco, State of California,

have invented certain new and useful Im provements in Multiple-Fuse Plugs; and I do hereby declare the following to be a full, clear, and accurate description of the invention.

This invention relates to new and useful im rovements in multiple fuse-plugs.

y invention is particularly applicable to tie type of fuse plug which involves the use of a multiple-fuse having a plurality of fuse arms or fuse elements which may be brought into the circuit in succession; in the operation of such fuses when one of the fuse arms burns out it is simply necessary to rotate a part of the plug through an angle to close the circuit through the next fuse arm or fuse. The general object of this invention is to produce a multiple-fuse plug of this type which is simple in construction and the parts of which can be readily detached to give access to the multiple-fuse to enable the same to be replaced after all of the arms have been fused, and to provide an interlocking connection between the relatively movable parts of the plug which will prevent the parts from being detached from each other until the fusible arms have all been burnt or fused, that is to say, I provide means for preventing disengagement of the relatively rotatable members from each other until the rotary member has made a complete revolution, but, at the same time, I provide a construction which will prevent a backward rotation of the contact which cooperates with the fuse arms; in this way I insure that all of the fusible arms or elements of the multiple-fuse will be used before detaching the plug.

Plugs of this type usually embody a central terminal, the inner end of which engages the central contact of the socket into which the plug is screwed; one of the objects of my invention is to provide an improved connection between the multiplefuse and this central terminal.

A further object of the invention is to provide a plug of simple con.-h-uction which can be readily taken apart 1,) an unskilled person and without the use of tools, to permit the replacingof a new multiple-fuse in it after the original fuse has been consumed; in other words, with my multiplefuse plug it is merely necessary to supply the user of the plug with a metallic part which constitutes the fuse proper; the remainder of the plug continues in use without change, thereby securing economy in the manufacture and use of this plug.

F urther objects of-the invention will appear hereinafter.

The invention consists in the novel parts and combinations of parts to be described hereinafter, all of which contribute to produce an efficient multiple-fuse plug.

A preferred embodiment of the invention is described in the following specification, While the broad scope of the invention is pointed out in the appended claims.

In the drawings:

Fig. l is a vertical section through a multiple-fuse plug embodying my invention.

Fig. 2 is a perspective of the multiplefuse plug shown in Fig. 1.

Fig. 3 is a perspective of the cap of the fuse removed and lying in an inverted position. the forward portion of the wall of the cap being broken away so as to further illustrate details of the construction of the cap and the means for securing a multiplefuse to it.

Fig. 4 is a plan of the cap.

Fig. 5 is a perspective of the central terminal of the pl ug.

Fig. 6 is a perspective showing a detail of the central contact or abutment of the plug which engages the central contact of the socket when the plug is screwed into the socket.

Fig. 7 is a plan of a multiple-false such as i may be employed in my plug.

Fig. 8 is a side elevation broken away and shown as if it were a developed section taken on the line 8-8 of Fig. 4 and located at the relatively fixed contactwhich cooperates with the fuse arms in succession as the cap is rotated; this view articularly illustrates the preferred means or preventing backward rotation of the cap on the body of the plug.

Fig. 9 is a horizontal section through the plug taken about on the line 99 of Fig. 1 and particularly illustrating the means for insuring the complete rotation of the cap on the body of the plug before the cap will come into a position in which it can be removed from the body.

In the drawing, 1 indicates the body or body portion of the plug. This body is provided with a central terminal 2, which is preferably of tubular form, the inner or cont-act end of the terminal being formed by a button or contact 3 which fits tightly into the inner cndof the tube and is exposed on the inner face or inner end of the plug.

The body 1 is of suitable insulating material such as porcelain or fibre and its inner portion is formed with a thread covered with a threaded metallic shell 1 which adapts the plug to be screwed into an ordinary socket.

This plug, as is usual in plugs of this type, includes two members connected together and relatively rotatable upon each other. In the present instance the body 1 is relatively fixed, and I provide a detachable cap 5 which operates as the rotatable member and also as the carrier for the multiple-fuse. The multiple-fuse 7 is preferably of substantially the form illustrated in Fig. 7, that is to say, it is constructed all in one piece with a central portion from hich fuse arms or fuses radiate.

In order to facilitate the attachment of the multiple-fuse 7 to the cap 5. I provide the cap with a central pin 6 which is received through a central opening in the multiple-fuse, the fuse being secured in place on the inner face of the cap by a nut 9 which screws onto the pin 6.

The body 1 is provided with a contact 10, the lower portion of which extends down and engages with the metal shell 4 (see Fig. 1) and the upper portion of this contact extends through the upper face of the plug, where it is twisted into a substantially horizontal plane so that it operates as a spring tongue projecting in the direction of rotation of the cap 5, that is to say, in a clockwise direction.

This contact or spring tongue 10 operates to prevent a rotation of the cap in one direction, that is to say, prevents a backward rotation of the cap. In order to accomplishthis some part of the multiplefuse or cap should engage the tip of the spring 1O when the cap is rotated to bring the next fuse arm into contact with it. In

the present instance the means cooperating with the contact 10, for this purpose. is the sides of the recesses or channels 8 which I provide on the inner face of the cap and which receive the fuse arms 7 respectively (see Fig. 3). The mode of operation of the spring contact 10 in the present embodiment of the invention is clearly illustrated in Fig. 8. 1

In order to indicate which ones of the fuse arms 7 have been burnt out I provide the cap 5 with a plurality of circumferentially disposed windows 11 which may be provided with mica plates covering same. \Vhen the fuse arm burns out this will be indicated by a blackened mica window above it.

The burning out of the fuse arms is facilitated by forming narrow necks on them as indicated at the points 14 in Fig. 7.

1 provide an interlocking connection between the relatively rotatable members which constitute the plug, that is to say, in the present instance the body 1 and the cap 5. which is so constructed as to enable these parts to be assembled by moving the cap longitudinally of the axis of rotation to seat it on the body 1; after which by rotating the cap the interlocking connection will prevent its being removed directly from the body; in other words, the cap cannot be lifted off of the body, but due to the interlocking connection cooperating with the spring 10" which prevents backward rotation of the cap, it will be necessary to rotate the cap through a complete revolution before it can be removed. An interlocking connection to produce this effect may consist simply of a lug or tongue, such as one of the tongues 13 shown in Fig. 3. By providing a longitudinal groove in the side face of the body. the cap could be seated on the body so that the lug or tongue would come into alignment with a circumferential groove on the body 1. By rotating the cap after seating it on the body. the tongue 13 would cooperate with the circumferential groove to prevent withdrawal of the cap from the body. However. such an interlocking connection involving the use of a single tongue would only operate at one point. I prefer to construct this interlocking connection in such a way that the cap will be locked against removal at several points around its circumference. In order to accomplish this I provide a plurality of tongues 13, for example, three tongues as illustrated in Fig. 9. These tongues are located a different number of degrees apart on the circumference of the cap, that is to say, they divide the circumference of the cap into unequal divisions or spaces. The body 1 is provided with longitudinal grooves 13 which are placed on the circumference of the body in positions to correspond with the tongues 13. Hence, the cap will seat on thebody only in one po sition; after being seated in this way if the cap is slightly rotatedthe lugs or tongues 13 pass into a circumferential groove 13 formed on the body. and this groove operates effectively to guide the cap in its rotation on the body and effectively prevents its removal until the cap has made a complete revolution. The contact spring 10 prevents the cap being rotated to the lef and so the plug may be removedfrom its socketby gripping the cap and turning the same to the left, in the same Way as any plug would be removed from its socket. When all six fuses have been exhausted, the fuses are renewed by removing the nut 9 and the remains of the burned fuses, after which another set of six fuses is slipped over the pin 6, after which the nut 9 is replaced and tightened into place. The cap 5 'is'then replaced and rotated to the right untilthe first fusible element is pressed upon, by the spring 10, when the circuit may be traced as follows: From 3 to 2, from 2 to 6, from 6 to 7, from 7 to 10, from 10 to 4, and so to the other side of the circuit wire.

It is evident that I have provided a multiple and refillable fuse plug in which the fusible elements may be readily placed in circuit successively as they become burnt out.

lit is understood that the embodiment of the invention herein described is only one of the many embodiments this invention may take, and'l do not wish to be limited in the practice of the invention, nor in the claims, to the particular embodiment set forth.

I claim:

1, In a multiple fuse plug, the combination of two relatively rotatable members havingan interlocking connection between them enabling one of the members to be rotated on the other, a multiple fuse having a plurality of fuse arms, one of said membersopcrating as a fuse carrier forthe same and having a plurality of recesses receivin the said fuse arms respectively, said inter ocking connection operating to prevent detachment of the rotatable'members from each other except whenheld in one 'predetermined angular position with relation to each other, and a resilient contact carried by the member opposite to the fuse carrier toengage the fuse arms and cooperating with'the same to prevent relative rotation of said members in one direction.

2,111 a multiple-fuse plug, the combination of two relatively rotatable members, a

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multiple-fuse having a plurality of fuse arms, one of said members having means for attaching the multiple-fuse thereto and operating as erase-carrier for the same, one of said members having a tongue and the other member having a groove extending substantially parallel with the axis of rotation and cooperating with the tongue to permit said members to be assembled by a-relative longitudinal movementalong the. axis of rotation, said longitudinal groove having a circumferential groove communicating therewith permitting relative rotation of said members, aresilient contact carried by the member opposite to the fuse-carrier, for engaging the fuse'arms in succession, said'fusecarrier having means cooperating with the permitting free rotation in the other direction, said tongue and said circumferential groove cooperating to prevent disengage-v ment of said members from each other until the rotation has progressed through a complete revolution.

8; In a multiple-fuse plug, the combination of a body and a cap mounted to rotate on the body, a multiple-fuse detachably mounted on the inner face of the cap and having a plurality of fuse arms, a resilient contact carried by the body for-engaging the fuse arms in successionwhen the cap is r0- tated on the body, said cap having means to cooperate with the resilient contact to prevent rotation of thecap in one direction and permitting free rotation of the cap in a forward direction, and a tongue and slotcon nection between the cap and the body operating to prevent disengagementof the cap from the body until the rotation of the cap has progressed through a complete revolution.

4. In a multiple-fuse plug, the combination of a body and a cap mounted to rotate on the body, a multiple-fuse detachably mounted on the inner face of the cap and having a plurality of fuse arms, a resilient contact carried by the body for engaging the fuse arms in succession when the cap is retated on the'body, said cap having means to cooperate with the resilient contact to prevent rotation of the cap in one direction and permitting free rotation of the'cap in a forward direction, said cap having a plurality of tongues located so as to divide the cireumference of the cap into unequal divisions, said body having a plurality of grooves located to correspond with the tongues and enabling the cap to be laced on the body by a relative movement 0? the cap on the body longitudinally of the axis of rotation, said body having a circumferential groove to co.- operate wit the tongues to prevent detach- .ment of the cap until its rotation has prolllll the members from each other, a multiplefusehaving a plurality of fuse arms, one of said members operating as a fuse-carrier for the same, and a resilient contact carried by. the other member for engaging the fuse arms, and operating to permit a relative ro- 1 tation of said members in one direction onl" fill said interlocking connection operating to prevent disconnection of one of the members from the other by longitudinal movement on the axis of rotation until the relative rotation has progressed through a complete revolution.

6. In a multiple fuse plug, the combination of two relatively rotatable members having an interlocking connection permitting the rotation of one member on the other, a multiple fuse having a plurality of fuse arms, one of said members having means for attaching the multiple fuse thereto and opcrating as a fuse carrier for the same, said interlocking connection operating to prevent detachment of the rotatable members from each other except in one predetermined angular position of said members with relation to each other, and a. resilient contact carried by the member opposite the fuse carrier to engage the fuse arms in succession, said fuse carrier having means cooperating with the resilient contact to prevent a relative rotation of said members in one direc tion and permitting free rotation of the same in the other direction.

7. In a multiple-fuse plug, the combination of an insulating body having a central terminal extending therethrough with a contact at the inner face of the body, the outer end of said terminal consisting of a resilient split tube, a cap rotatably mounted on the body. a multiple-fuse secured to the cap and rotating with the cap, said cap having a metallic pin in contact with the multipletuse and received within the split tub-e when the is placed on body, a metallic shell on the outer side of the insulating body formed into threads to screw into the socket, a con-- tact connected with the metallic shell entending up to the outer face of the body,

and having a resilient tip to engage with thetus aims in succession when the cap is rotated, and means cooperating with the resilient tip to prevent rotation of the cap in one direction.

8. In a multiple-fuse plug, the combination of an insulating body having a central terminal extending therethrough with a contact at theinner face of the body, the outer end of said terminal consisting of a resilient split tube, a cap rotatably mounted on the body, a multiple-fuse secured to the cap and rotating with the cap, said cap having a metallic pin in contact with the multiplefuse and received within the split tube when the cap is placed on the body, a metallic shell on the outer side of the insulating body formed into threads to screw intoa socket, a contact connected withthe metallic shell extending up to the outer face of the body, and having a resilient tip to engage with the fuse arms in succession when the cap is rotated, and means cooperating with the resilient tip to prevent rotation of the cap in one direction, the said cap having a tongue and said body having a longitudinal groove to receive the tongue when the cap is seated on the body and a circumferential groove communicating with the longitudinal groove to prevent detachment of the cap until the rotation of the cap on the body has pro gressed through one revolution.

9. ln a multiple-fuse plug, the combination of a body having a central terminal extending therethrough, having a tubular outor end, a rotatable cap with a multiple-fuse mounted on the body, having a central in in metallic contact with the fuse, receive in the tubular end of the terminal, the said upper end of said terminal being split and operating to exert spring pressure upon the pin, when the same is inserted,

in testimony whereof I ailin my signature.

N, M. STEPHENSON. 

